A bag contains 5 red, 3 black balls and another bag contains 4 red and 5 black balls. One of the bags is chosen at random and a draw of two balls is made from it. The chance that one id red and the other is black is

A lot consists of 12 good pencils, 6 with minor defects and 2 with major defects. A pencil is drawn at random. The probability that this pencil is not defective is

Mr. A is called for 3 interviews .There are 5 candidates at the first interview, 4 at the second and 6 at the third .If the selection of each candidates is equally likely then the probability that A will be selected for at least  one post is

A bag contains2whit, 3 black and 4greenballs. If2 balls are drawn from it, one after another then the probability that the first one is white and the second one is black is

From an urn containing 3 white and 5 black balls , 4 balls are transfered in to an empty urn. From this urn a ball is drawn and found to be white. The probability that out of four balls transfered 3 are white and 1 is black is

If the polar of P with respect to the circle x²+y²=a² touches the parabola y²=4ax, then the locus of P is

The probabilities of problem being solved by two students are 1/2 and 1/3.Find the probability of the problem being solved.

If 10 balls are to be distributed among 4 boxes, that the probability for the first box always to contain 4 ball is

Card is drawn at random from a pocket of 100 cards numbered 1to 100. The probability of drawing a number which is a square is

The odds against A solving a problem are 3 to 2 and the odds in favour of B solving the same problem ae5 to 4.Thenthe probability that the problem will be solved if both of them try the problem is